Loud-speaker



NOV. 22, 1932. W MUENCH 1,888,769

LOUD SPEAKER IIN l l uw' uw' Nov. 22, 1932. w. MUENCH LOUD SPEAKER Filed @mila-1929 4 sheets-sheet 2 Nov. 22, 1932.

LOUD SPEAKER Filed Jan. 16, 1929 4 Sheets-Sheet 3 Nov. 22, 1932. w. MUENCH 1,888,769

LOUD SPEAKER Filed Jan. 16, 1929 4 Shets-Sheet 4 mfc I Mmnmmmmu,

HIHHIHI Ej I Patented Nov. 22, 1932 UNITED STATES PATENT OFFICE WALTER MUENCH, F BROOKLYN, NEW YORK LOUD-SPEAKER Application filed January 16, 1929.

the loud speaker unit and the sound spreader whereby the length of the inner and outer communicating tone Chamber may be varied.

Another object of my invention resides in the construction of a loud speaker having a uni-directional flat spiral producing inner and outer communicating tone chambers between a loud speaker unit and a sound spreader in which the cross sectional area of said tone chambers gradually increase, so that eX- 0 ponential sound volume is obtained at the sound speaker.

Primarily, my invention relates to loud speakers preferably of the portable type embodying the principle of a uni-directional,

continuous tone chamber formed by a flat,

smooth surfaced spiral of non-vibratable material arranged or wound so that the cross sectional arca of the inner and outer tone chambers gradually increase from the loud speaker unit to the sound spreader so as to produce an appreciable undistorted amplification of the impressed sound waves in said speaker.

To enable others skilled in the art to more fully comprehend the underlying features of my invention, reference is riad to the accompanying drawings wherein Fig. 1 is a front view showing the sound spreader and front spiral clamping disk rel moved.

Fig. 2 is a side view partly in section.

Fig. 3 is a side view, partly in section of a modified form of the invention.

Fig. l is an end view partly in section.

Fig. 5 is a front view partly in section of another modified form of the invention.

Fig. 6 is a side view of the form shown by Fig. 5 showing the interior construction, one conical side piece and loud speaker unitbe- 0 ing removed.

Serial No. 332,848.

Fig. 7 is a side view partly in section of a still further modified form of the invention.

Fig. 8 is a view taken on the line 8-8 of Fig. 7.

Referring now to the drawings, 5 designates a substantially rectangular base of any suitable material having a pair of pillars or posts 6, 7 mounted thereon preferably adjacent the rear or back of the base. The

pillars or posts carry a frame consisting of top and bottom cross members 8, 9, integral with curved or segmental, connecting meinbers 10, 11, said cross members being retained in suitable slots or grooves formed in the inner side of the posts.

The base 5 has mounted thereon, a flanged rest 12, the front and rear spaced walls 13, 14 of which are concentric to the bottom of front and rear disks 15, 16. Between the disks 15, 16, I provide a broad, flat spiral 17. The two disks and the spiral strip are preferably of non-vibratable material such as metal, wood, glass, bakelite, rubber or celluloid. Under certain conditions, the surfaces of the spiral and the inner surfaces of the side disks are preferably coated or covered with any suitable composition to assure a smooth and glossy finish so as to avoid any possible friction to impede the sound waves.

When metal or a metallic composition is employed in the manufacture of the loud speaker, it is advisable to cover or coat the coinplete tone chamber with a coating of lacquer, rosin, pitch or rubber. Such coating can easily be applied by dipping in a tank containing the preferred solution. A coating of the solution may be applied to any or all of the forms shown, regardless of the material of construction of the disks and spiral. However, in instances where metal or metallic 90 compositions are employed, a coating of soft or medium soft rubber is highly desirable so as to avoid and overcome all metallic sounds and what is known as blasting sounds cominner tone chamber 19. The inner tone chamchamber.

Vio

ber does continue in successive spiral turns until it finally terminates in an outlet chamber 20, the diameter of which is at least three times the width of the inner or outer tone The outlet is in direct cominunication with a flared sound spreader 20a. The inlet of the outer spiral tone chamber is closed by a cover 21 having an opening over which is mounted the usual loud speaker unit 22.

The flat spiral and covering disks are fastened together by means of bolts 23 having countersunk heads 24 passing through the respective front and rear disks and both top and bottom cross members of the frame. Similar bolts join the disks between the cross bars, and the bottom of said disks are joined to the front and rear walls of the base rest in the same manner. lAll of the bolts are fastened and locked by means of lock nuts at the rear. From the above construction, it will be seen that the locking bolts join the front and rear disks to the frame and the base rest and retain the spiral in position therebetween, thus rendering the device easy to assemble.

In the form of the invention shown by Figs. 3 and 4, a reversal of the principle employed as shown by Figs. 1 and 2, is adopted and permits of different design and construction. The base 5a and base rest 6a is of a similar construction to supporta pair of flat side disks 7a, 8a. In this instance the frame may be dispensed with, the loud speaker being supported by the base. The flat spiral 9a may be glued, cemented or otherwise retained in notches or slits formed in opposed, inwardly extending projections or lugs 10a integral with the inner walls of the disks, as shown clearly by Fig. t. The spiral extends from the axial center 11a to a point adjacent the periphery of the disks, thus producing an inner, spiral tone chamber 12a and an outer spiral tone chamber 13a which merge,

the width and cross sectional area of said 4 chambers gradually and uniformly increasing to an outlet 14a where the maximum volume of sound is projected. The loud speaker unit 15a may be similarly fastened to a disk 16a. This form of the invention, permits ,of the attachment for a removable, flared trunco-coincal, sound spreader 17a to the outlet, the outer end of said spreader being preferably provided with a cap 18a of a curved screen mesh of wire or textile material which serves for ornamental or decorative purposes. The length of the spiral and the width of the tone chambers may in each instance be varied if so desired in accordance with the intensity of the speaker unit employed and the maximum and minimum sound amplification desired.

In Figs. 5 and 6 the base 5b and base rest 6b are designed to support a pair of similar, truste-conical, shaped sides 7b, 8?), the ina-:Li-

65 mum diameter of which is determined by the number of turns and width of the spiral forming the tone chambers. The continuous spiral 9b extends from a point 10?) adjacent the inner edge of the sides, to the extreme outer edge 11b, the diameter of the inner and adjacent tone chambers 12b, 18?), 146, gradually increasing to the outlet 15?) at the top of the loud speaker. In this instance, a wide, flaring spreader 166 may be detachably connected to the outlet or end of the outer tone chamber which may or may not be provided with a cap or covering similar to that illustrated by Fig. 3. The loud speaker units 176, 18?) are positioned opposite to each other within the frustocone shaped sides so as to project the sound waves into the central tone chamber.

The ferm of the invention shown by Fig. 7 comprises a fiat base 5c having` a flat, rear upright 6c to which is attached a back cover 7c. A front, frusto-cone shaped cover 80 is joined and preferably integral with a circular, flared sound spreader 9c having a neck 10c. In this form, the fiat spiral 110 is tapered along one edge, to conform with the cover 8c of the sound spreader and the opposite straight edge engages the back cover as shown by Fig. 7. The width of the spiral thus increases from its outer to its inner end producing the outer tone chamber 120 and inner continuous tone chamber 130, 1&0. rI`he maximum diameter of the inner tone chamber is at a point adjacent the neck of the sound spreader. The loud speaker unit 150 is necessarily located at the entrance to the outer tone chamber thus permitting the volume to gradually increase to the outlet or sound spreader as abovev described.

In all of the above constructions, represented by the various modifications, it will be noted that the spirals form tone chambers in which the sound waves are projected forward in a unidirectional, circular spiral path, that is from the center of the loud speaker to an outlet at the top or from an inlet at the top to an outlet at the center. By this unidirectional spiral tone chamber arrangement, interferences of sound waves resulting in echoes and sound distortions within the loud speaker are avoided. The solidness of the material permissible in this novel loud speaker renders vibrations and consequent resonance due to the timber of the material used, a very negligible factor in consequence of which sound interference, common to horns and other irregular shaped tone chambers, are overcome. rlhere is an appreciable distance and time factor between the impulse at the loud speaker unit and the sound outlet, the tone and volume being concentrated in its passage through the tone chamber, amplification of the impressed sound waves is thereby made possible. By the use of many spiral turns, but with a small angular rise in the overall length of the spiral strip, exponential amplification is obtained with a resultant of perfect modulation of tone. Greater volume is possible when the angular rise in the spiral is made larger, though the perfect modulation is not present.

lNhile I have shown and described my invention with some degree of particularity, it will be realized that other modifications and changes may be resorted to under special, conditions. I therefore do not wish to be limited and restricted to the enact details shown and described but reserve the right to make such changes and modifications as may fairly i'all within the scope of the subject matter now being claimed.

lVhat I claim as new and desire to secure by Letters Patent is:

l. In combination with the cochleate sound channel of a loud speaker, a partition bent into a flat spiral separating adjoining convolutions of said sound channel, and front and rear walls, between which said partition is assembled.

2. In combination with the cochleate sound channel of a loud speaker, a partition bent into a substantially flat spiral 'forming a wall common to adjoining convolutions of said sound channel, and front and rear walls, between which said partition is assembled.

3. In combination with the cochleate sound channel of a loud speaker, a partition bent into a substantially flat spiral, and side walls uninterruptedly extending over the sides of a plurality of convolutions of said sound channel, said partition being assembled between said walls,

4. In combination with the cochleate sound channel of a loud speaker, a partition separating adjoining convolutions of said sound channel, and fiat side walls substantially radially extending over thev sides of a plurality ef said convolutions, said partition being assembled between said walls.

5. In combination with the cochleate sound channel of a loud speaker, a spirally disposed partition forming a wall common to adjoining convolutions of said sound channel, and side walls angularly assembled with said partition and extending over the sides of a plurality of said convolutions, said partition being assembled between said side walls.

6. In combination with the cochleate sound channel of a loud speaker, a spirally disposed partition forming a wall of substantially uniform thickness common to adjoining` convolutions of said sound channel, the cross-section of said cochleate channel gradually increasing from the inlet to the outlet of said channel, and front and rear walls between which said partition is assembled.

7. In combination with the cochleate sound channel of a loud speaker, a spirally disposed partition separating adjoining convolutions of said sound channel, and side walls angularly facing said partition and radially eX- tending over the sides of a plurality of said convolutions, the cross-section of said cochleate channel gradually increasing from the inlet to the outlet of said channel, said partitions being assembled between said side walls.

8. In combination with the cochleate sound channel of a loud speaker, a. spirally disposed partition forming a wall common to adjoining convolutions of said sound channel, said spirally disposed partition being coated to reduce sound propagation through the walls between adjoining convolutions.

9. A loud speaker, comprising two substanstantially registering side walls, and a flat spiral partition assembled between said walls, said partition separating the convolutions of a cochleate sound channel.

lO. A loud speaker, comprising two substantially registering side walls, and a spiral partition disposed and clamped between said walls, said partition separating the convolutions of .a cochleate sound channel.

ll. A loud speaker comprising a side wall, a cone-shaped side wall substantially registering with said lirst wall, and a iiat partition spira-ily disposed between said walls and forming a cochleate sound channel between and with said walls.

12. A loud speaker comprising two substantially registering side walls, a flat spiral partition coaXially disposed and assembled between and flanged by said walls and forming a cochleate sound channel between and with said discs, and a sound reproducer and a sound spreader connected with the end of smallest and largest cross-section, respectively, of the channel extending between said walls and partition.

13. A loud speaker comprising a side wall, a cone-shaped side wall substantially registering with said first wall, a flat partition spirally and coaxially assembled between, flanged by and forming a channel between said walls and forming a cochleate sound channel between and with said discs, and a sound reproducer and a sound spreader connected with the end of the smallest and largest cross-section, respectively, of said channel.

14. A loud speaker comprising a pair of side walls, one of which has the shape of a cone, a flat partition spirally and coaXially disposed between and flanged by said walls and forming a cochleate channel between and with said walls, and a sound reproducer and a sound spreader connected with the ends of said channel.

l5. A loud speaker comprising registeringly disposed cone-shaped side walls and a spirally disposed iiat partition forming a sound channel between and with said coneshaped walls.

16. A loud speaker comprising registeringly disposed inverted cone-shaped side walls and a spirally disposed flat partition forming a sound channel between and with `said `cone-shaped walls.

17. A loud .speaker comprising coaxially disposed inverted cone-shaped side walls, a -spirallly disposed flat partition forming a coohleate sound Channel between and with said .cone-shaped walls, and a sound reproduoer and a sound spreader connected with the end of the smallest and largest cross-seotion, respectively, of said channel.

18. In a loud speaker7 oppositely disposed substantially iiat side walls and partitions extending between and abutting upon said walls and dividing theV space between said walls into adjoining sound Channels.

19. In a loud speaker, oppositely disposed vside walls and partitions vextending between and abutting upon said walls and dividing thel space 'between said walls into adjoining yangular sound channels.

20. In a loud speaker, a partition common -to adjoining passages of tlie sound channel7 and a rubber-like coating on said partition.

2l. In a loud speaker, a metallic partition common to adjoining passages of the sound cliannel7 and a rubber-like Coating on said partition. f

In testimony whereof I .alix mv signature.

WALTER MUENCH. 

